#include<bits/stdc++.h>
#define y1 Y1
#define fi first
#define endl "\n"
#define se second
#define PI acos(-1)
#define int long long
#define pb(x) push_back(x)
#define PII pair<int, int>
#define Yes cout << "Yes\n";
#define No cout << "No\n";
#define YES cout << "YES\n";
#define NO cout << "NO\n";
#define _for(i, a, b) for(int i = a; i <= b; ++i)
#define IOS ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
using namespace std;

const int N = 2e5 + 10;
int a[N];
int x, y, l, r, ret = 0;
string s;

signed main() {
	IOS;
	cin >> x >> y >> l >> r;
	if(x > y) {
		swap(x, y);
	}
	int t = __gcd(x, y);
	x /= t;
	y /= t;
	
	int i = 1;
	while(i * x <= r && i * y <= r) {
		if(x * i >= l && i * y >= l)ret ++ ; 
		i ++ ;
	}
	cout << ret << endl;
	return 0;
}

